Interpretive Summary: The use of methyl bromide as a fumigant for disinfesting fruit is expected to be restricted by increased regulation. At the USDA, ARS Yakima Agriculture Laboratory, heat treatments are being developed to replace methyl bromide fumigation to control quarantine pests of fruits. Mortality of fifth instar codling moth larvae was determined over a range of temperature-time exposures. Also, the lethal effect of the rate of temperature increase was determined. The amount of energy needed to kill the insect was determined then from these results. These energy requirements were expressed as equations from which mathematical models were dereived. These models indicate the most effective process for quarantine control. This information has been used to design specific heat treatments with minimum impact on commodity quality.

Technical Abstract:
Thermal death kinetic parameters of fifth-instar codling moths (Cydia pomonella (L.)) and the effect of three heating rates ( 1,10 and 18 degrees Cmin-1) on larvae mortality were determined by a heating block system. The insects were heated to four temperatures (46,48,50 and 52 degrees Celsius) held for predetermined periods followed by 24 hours storage at 4 degrees Celsius before mortality evaluation. Thermal death kinetics for fifth-instar codling moths followed a .05th order of kinetic reaction. Minimum time required to achieve 100 percent mortality of a given population decreased with temperature in a semi- logarithmic manner. No larvae survived was observed in sample of 600 insects after holding a 46,48,50 and 52 degrees Celsius for 50,15,5 and 2 minutes respectively. Activation energy for thermal kill of fifth -instar codling moths at the heating rate of 18 degrees C min-1 was estimated to be about 472 kJmol -1. The lethal time cumulated during the ramp period was about 1.8, 0.2 and .01 minutes for the heating rates of 1, 10 and 18 degrees Celsius min -1, respectively